A NZ one is $99 from countdown...  http://shop.countdown.co.nz/shop/ProductDetails?Stockcode=769498&name=nescafe-dolce-gusto-coffee-machine-automatic

Better to just throw the one you got from Ebay out when you get it and buy a NZ new one as a 230V -> 110V transformer which can do 1500W will cost a lot more than the Coffee Machine itself!


 

Short answer, yes you will definitely need an adaptor. And you will probably need a step down transformer as well. As guessing that it will be designed for American 110V only. Unlike things like laptop power supplies which will work on almost any voltage.

And depending on how much power it draws you will need a big (and expensive) stepdown transformer. Also the lower mains frequency in NZ can cause problems as well. Since NZ is 50Hz and USA is 60Hz. This will cause some types of electric motor to run slower than normal. It can also cause some types of electric motors and transformers to overheat. And if the appliance has an inbuilt clock then it might run slow as well. (won't keep correct time).

http://www.jaycar.co.nz/productView.asp?ID=MF1086&w=mf+1086&form=KEYWORD

Even this transformer may not be powerful enough to run a coffee machine. Since that one can output 8.6A But US sockets are rated at 15A.